The present invention relates broadly to a battery test apparatus and in particular to a nickel cadmium battery conditioner and tester apparatus.
It is very necessary to know the capacity capabilities of a rechargeable battery in order to determine its condition for use in a particular circuit environment. In other words, if the rate at which a battery loses charge which is in excess of a minimally acceptable rate, the terminal voltage of the battery would fall below the rated voltage in a comparatively short time and thereby render the battery useless or unfit for use in its intended application.
Therefore, it is desirable, and in many instances essential in remotely operated nickel-cadmium battery systems, to determine the state-of-charge of the batteries prior to installation in such systems due to the tendency of the batteries to deteriorate in an unpredictable manner. One prior art system that has been used to determine the battery capacity of nickel-cadmium batteries is the timer-charger system that employs a manual charge-discharge procedure for determining the ampere-hour discharge capacity of the battery. However, such systems generally involve test procedures of relatively long duration, up to 20-30 hours to complete. Moreover, since these systems determine the total ampere-hour capacity at a given discharge rate, these systems obviously have not been suitable as state-of-charge testers.
There have been numerous approaches have been taken to provide a device capable of indicating the state of charge or deterioration of such batteries. These approaches have involved various types of apparatus to provide a test for the conductivity of the electrodes of the battery, since such conductivity changes with cycling and charge.
Additional other techniques and devices for the testing of battery conditions have been devised wherein the specific gravity and/or chemical composition of the battery electrolyte is tested. Such tests are generally complex, inaccurate, and conducive only to a manual rather than an automatic mode of operation.